This paper is concerned with an application study of model-based fault detection method to a ship propulsion system. When modeling the object system, Quasi-ARMAX model with multi-model form is used. In this model, the...
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Advances in scheduling theory have given designers of control systems greater flexibility over their choice of timing requirements. Advances in scheduling theory have given designers of control systems greater flexibi...
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Advances in scheduling theory have given designers of control systems greater flexibility over their choice of timing requirements. Advances in scheduling theory have given designers of control systems greater flexibility over their choice of timing requirements. This could lead to systems becoming more responsive, more flexible and more maintainable. However, experience has shown that engineers find it difficult to exploit these advantages due o the difficulty in determining the "real" timing requirements of systems and therefore the techniques have delivered less benefit than expected. Part of the reason for this is that the models used by engineers when developing systems do not allow for emergent properties such as timing. This paper presents an approach and framework for addressing the problem of identifying an appropriate and valid set of timing requirements and their corresponding control parameters based on a combination of static analysis and simulation.
When the process uncertainty size increases, even linear minimum phase systems must sacrifice desirable aggressive feedback control benefits to avoid an excessive 'cost of feedback', while preserving the robus...
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Tracking feedback control trade-offs increase dangerously with arbitrarily large uncertainties in the process mode!. This is shown by the bounds in the QFT domain. In this context, the paper develops a theory on the c...
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A newly high performance ATM switch, called fast multicast parallel-Banyan switch, has been introduced for handling multirate traffic and higher bit rate services required for ATM cell processing specially in the case...
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A newly high performance ATM switch, called fast multicast parallel-Banyan switch, has been introduced for handling multirate traffic and higher bit rate services required for ATM cell processing specially in the case of bursty data. The architecture is based on several key principles: non-blocking, self-routing, output queuing for delay and throughput enhancement, levels of service priority required for maintaining QoS, high level of parallelism for achieving scalability, reliability and higher speed, and multicast function with efficient use of bandwidth. The switch is modeled analytically and simulated. The experiment results are similar to the analytical results. The tandem-Banyan multicast switch is also analytically modeled. The switch performance is evaluated in terms of cell loss probability, speed, delay, and maximum number of transmitted multicast cells in a time slot then it is compared with similar designs based on different approaches: tandem-Banyan, Clos network and multicast tree. The switch is found to be of similar or less cell loss probability and delay but it provides a higher bit rate services independently form the multicast load.
The purpose of this paper is to reduce the communication costs for applications that send the same data to multiple recipients across a wide-area network. The existing multicast and broadcast routing mechanisms are no...
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The purpose of this paper is to reduce the communication costs for applications that send the same data to multiple recipients across a wide-area network. The existing multicast and broadcast routing mechanisms are not efficient in terms of storage, bandwidth consumption and traffic concentration: data packets or membership information are occasionally sent over many links that do not lead to the receivers or senders, respectively. This paper constructs two different delivery trees, the collection of nodes (routers) and the links that a multicast or a broadcast packet traverses, by two heuristic algorithms. The first tree is a single spanning tree to deliver broadcast packets with minimal network cost and minimal number of traversed links. The second tree is a single minimal bandwidth group-shared tree (MBGST) per group, to deliver a multicast packet. This tree is a construction of shortest-path multicast tree (SPT) in order to minimize the number of traversed links. The results indicate a 45% reduction of the multicast load independent from the network growth. This realizes a greater traffic concentration and it balances the load over the traversed routers (nearly equal fan-out). This reduces the maximum fan-out of each node, which avoids the CLR increasing at the switching node. The multicast MBGST tree is suitable for constructing the group-shared tree required by PIM-SM protocol, which uses both SPT and group-shared tree for multicast packet delivery according to the application's delay sensitivity. The correctness, stability, optimality, fairness in distributing load over the traversed routers, and scaling properties of these algorithms make it well suited for large heterogeneous networks.
This article addresses a method for discrete-time H∞- control based on J-lossless factorisations of chain scattering representations of a plant. Delta-domain state space formulae for both J-lossless and dual J-lossle...
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This article addresses a method for discrete-time H∞- control based on J-lossless factorisations of chain scattering representations of a plant. Delta-domain state space formulae for both J-lossless and dual J-lossless factorisations are given. Optimal controllers are obtained via solving two coupled δ-domain algebraic Riccati equations. A relative condition number is utilised as a measure of numerical conditioning of the δ-domain algebraic Riccati equation and it is shown that the proposed method of controller synthesis is much better-conditioned than its counterpart version based on the common forward shift operator. Two numerical examples are given to illustrate the method.
The problem of identification/tracking of quasi-periodically varying processes is considered. Two solutions to this problem are presented, First the global search algorithm is derived. Then its decoupled version. with...
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The problem of identification/tracking of quasi-periodically varying processes is considered. Two solutions to this problem are presented, First the global search algorithm is derived. Then its decoupled version. with a highly parallel computational structure, is proposed.
This article addresses a new development of robust pole placement design in the delta domain for single-input single-output (SISO) control systems. Problems of how to obtain both the nominal as well as robust closed-l...
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This article addresses a new development of robust pole placement design in the delta domain for single-input single-output (SISO) control systems. Problems of how to obtain both the nominal as well as robust closed-loop stability and performance are considered. The approach is based on a robust pole placement methodology that uses two sets of coupled Diophantine equations and the Q-parameterisation paradigm. The method can be applied both for minimum-phase and non-minimum-phase uncertain systems. A numerical example is given to illustrate the method.
Availability of large full-text document collections in electronic form has created a need for tools and techniques that assist users in organizing these collections. Document clustering is one of the popular methods ...
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Availability of large full-text document collections in electronic form has created a need for tools and techniques that assist users in organizing these collections. Document clustering is one of the popular methods used for this purpose. In this paper, we propose the neural network based document clustering method by using a hierarchically organized network built up from independent Self-Organizing Map (SOM) and Adaptive Resonance Theory (ART) neural networks. We present clustering results using the REUTERS corpus and show an improvement in clustering performance using both entropy and F-measure as evaluation measures.
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